Assume the current stock price of Company X is $600. The stock price will either increase by 10% or decrease by 10% in the first month.

If the price increases in the first month, it will go up by $100 or down by $80 in the second month.

If the price decreases in the first month, it will go up by 10% or down by 10% in the second month.

The risk-free interest rate is 5% per month.

Assume there is a 2-month put option with an exercise price of $600.

Use the replicating portfolio approach to calculate the 2-month put premium today.